This invention relates to a magnetic head of a main pole magnetizing type for recording information vertically in a magnetic medium.
Heretofore magnetic heads of main pole magnetizing type have been known for advantageously recording data vertically on one side of a recording medium 3 comprising a base film 1 and a magnetic layer 2 as shown in FIG. 1.
A typical construction of such a magentic head comprises a core 5 made of a soft magnetic material having a magnetizing coil 4 embedded near the end engaging the magnetic medium, a guard member 6 of non-magnetizing material secured to an upper part of the core 5, and a thin magnetic layer 7 provided between the opposing surfaces of each half of the cores 5 and the guard member 6. A conventional method of producing the magnetic head is shown in FIGS. 2(a) through 2(e). A groove 9 is formed on the upper surface of a core material 8 formed of a soft magnetic material such as ferrite, Sendust, laminated Permalloy and the like (see FIG. 2(a)) and having the shape of a bar of rectangular section. The surface of the core material 8 containing the groove is then inclined as shown in FIG. 2(b), and a body of material 10 is placed over the inclined surface to form a planar top surface, as shown in FIG. 2(c). The body of material 10 is to form the guard member 6 and is comprised of a wear-resistant, non-magnetizing material such as a ceramic, glass, a composite material of carbon and metal or the like bonded to the inclined surface by fusing with glass or the like. Then a surface 12 of the combination 11 of the core material 8 and the planar material 10, on which a thin magnetic layer 7 constituting the main pole is to be formed, is ground, and on this surface 12 is deposited a thin magnetic layer 7 of, for instance, Permalloy or amorphous cobalt-zirconium by use of a vapor-deposition, sputtering, plating process or the like, with the combination 11 thus formed with the magnetic thin layer 7 being thereafter annealed to form the structure of FIG. 2. Then another combination 13 subjected to the production steps FIGS. 2(a) through 2(c) is bonded to the combination 11 (see FIG. 2(e)), and the thus bonded product is ground on the upper surfaces of the planar material 10 to form the curved surface of the guard member 6, as shown by dotted line in FIG. 2(e). The elongate product is then sliced into pieces each having a desired thickness, and a magnetizing coil 4 is wound in the groove 9 of the core 5 of each piece to provide a magnetic head.
However, the combination 11 has to be annealed after the deposition of the thin magnetic layer 7, and this annealing serves to increase the demagnetizing force of the soft magnetic core material 8, thus deteriorating the property of the same.